What is the meaning of change of angular momentum of a ballistic object during its flight?Throughout the stones' flight, both gravity and air resistance are acting on them to change their momentum. Gravity exerts a force on an object pulling it towards the center of the earth - changing it's momentum. Air resistance applies the same way, though from the trajectories graphed it looks like air resistance is being ignored. So as soon as the rock leaves the hand of the person throwing it, gravity begins changing it's momentum.